Calling an ongoing callback on a deferred object of a given args (progressCallbacks)
Normally, only one deferred creator should call this method; you can prevent other code from changing the state of Deferred or return a restricted committed object report status via deferred.promise()
When deferred.notify is accessed, any progressCallbacks can be added by accessing deferred.then or deferred.progress . Callbacks are executed in the order in which they are added. Each time you pass the args callback from .notify(). Any deferral after .notify() is resolved or rejected (or any progressCallbacks added afterwards) is ignored. For more information, please refer to the document Deferred object .
Optional parameters passed to the ongoing callbacks (progressCallbacks)